Fragmentation functions and parton distribution functions for the pion with the nonlocal interactions

Abstract

We study the unpolarized fragmentation functions and parton distribution functions of the pion employing the nonlocal chiral quark model. This model manifests the nonlocal interactions between the quarks and pseudoscalar mesons in the light-cone coordinate. It turns out that the nonlocal interactions result in substantial differences in comparison to typical models with only local couplings. We also perform the high Q 2 -evolution for our results calculated at a relatively low renormalization scale Q 2 ≈ 0.36 GeV 2 to be compared with the experimental data. Our results after evolution are in qualitatively good agreement with those data.

Fragmentation and quark distribution functions for the pion and kaon with explicit flavor-SU(3)-symmetry breaking

“…These values are obviously larger than those in other models. It tells us that substantial PS-meson cloud effects have already been included in our model as discussed in the previous work [40]. Actually the momentum-dependent effective quark mass contains part of the PS-meson cloud effects, since in usual Dyson-Schwinger approaches [27] the effective quark mass corresponds partially to the dressed quark mass generated by the PS-meson could.…”

“…(20) and (21), satisfying the normalization condition for f φ q (x) for brevity [40]. This treatment is supposed to compensate the absence of the nonlocal contributions phenomenologically.…”

“…As we have done in our work in SU(2) sector [40], we reach a concise expression for the elementary fragmentation function q → φq from NLChQM:…”

“…As in [40], a free and finite-valued parameter δ in the denominator to avoid the unphysical singularities which appear in the vicinity of (z, k T ) = 0, due the present parametrization of the effective quark mass as in Eq. (7).…”

Analysis of the masses and decay constants of the heavy-light mesons with QCD sum rules

“…There has been much theoretical work on the decay constants of the heavy-light mesons, such as the QCD sum rules [2][3][4][5][6][7], the lattice QCD [8][9][10][11][33][34][35][36][37][38], the BetheSalpeter equation [39,40], the relativistic potential model [41][42][43], the field-correlator method [44], the light-front quark model [45][46][47], the chiral extrapolation [48], the extended chiral-quark model [49,50], the constituent quark model [51], etc.…”